Optical disc reproduction method and optical disc reproduction apparatus

ABSTRACT

A method of reproducing an optical disk that that shortens the time between optical disk insertion and implementation of a standby mode enabling reproduction is provided that comprises a step of reading parameters stored in a nonvolatile memory, a step of deciding whether the optical disk can be properly reproduced using the read parameters, a step of, when it is found that the optical disk cannot be properly reproduced using the parameters, conducting a focusing search, reflection level detection, tracking error signal amplitude measurement and the like with respect to the optical disk, a step of specifying new parameters based on the result, and a step of storing the new parameters in the volatile memory.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a method of reproducing anoptical disk and an optical disk reproducing apparatus, moreparticularly to a method of reproducing an optical disk and an opticaldisk reproducing apparatus that shorten the time between optical diskinsertion and implementation of a standby mode enabling reproduction.

DESCRIPTION OF THE PRIOR ART

[0002] Optical disks, typically CDs and DVDs, are used in large numbersas recording media for recording digital data. Apparatuses forreproducing such optical disks can be classified into two majorcategories, those of the type that reproduce only a specific kind ofoptical disk and those of the type that can reproduce multiple kinds ofoptical disk.

[0003] For example, the ordinary CD player can reproduce only CDs andtherefore belongs to the former type, while the ordinary DVD player canreproduce both CDs and DVDs and therefore belongs to the latter type.

[0004]FIG. 4 is a flow chart schematically showing the sequence ofoperations conducted in the former type of optical disk reproducingapparatus between optical disk insertion and transition to the standbymode.

[0005] As shown in FIG. 4, the optical disk is first inserted into theoptical disk reproducing apparatus (step S1), whereafter a controlcircuit in the apparatus operates a spindle motor to rotate the opticaldisk and operates an optical head to project a laser beam onto therecording surface of the optical disk (step S2). Next, the focusing ofthe laser beam is turned on based on a focusing parameter stored in theoptical disk reproducing apparatus beforehand (step S3), whereafter thetracking of the laser beam is turned on based on a tracking parameteralso stored in the optical disk reproducing apparatus beforehand (stepS4). The focusing and tracking parameters are both parameters specificto the type of optical disk (e.g., CD) reproducible by the optical diskreproducing apparatus (e.g., CD player). As a result, the optical diskreproducing apparatus is put in a state that enables reading of datarecorded on the optical disk.

[0006] Once the laser beam focusing and tracking have been set in thismanner, the control circuit in the apparatus conducts initializationconsisting of address detection, reading of file management informationand the like (step S5), and upon completion of the initialization theapparatus enters the standby mode (step S6). Standby is a state in whichthe apparatus waits for an instruction from the user, and when the userenters an instruction to reproduce the optical disk, reproductionbegins.

[0007] However, in the latter type of optical disk reproducingapparatus, i.e., the type of optical disk reproducing apparatus that canreproduce multiple types of optical disks (e.g., a DVD player), a stepof discriminating the type of optical disk inserted is required duringthe sequence of operations conducted between optical disk insertion andtransition to standby, because the parameters for turning on thefocusing and the tracking differ depending on the type of optical diskinserted (e.g., CD or DVD). In latter type of optical disk reproducingapparatus, therefore, more time is needed between optical disk insertionand transition to standby than in the former type of optical diskreproducing apparatus.

[0008] Even in the case where the user mainly uses only a specific typeof optical disk (e.g., DVDs) and almost never uses another type ofoptical disk (e.g., CDs), this step of discriminating the type ofoptical disk is nevertheless conducted every time an optical disk isinserted, so that under such circumstances, a particular the user iscaused particular stress.

[0009] In the type of optical disk reproducing apparatus that canreproduce multiple types of optical disks, therefore, a method has beendesired that can shorten the time required between optical diskinsertion and transition to standby. A need has also been felt for anoptical disk reproducing apparatus that can reproduce multiple types ofoptical disks that is capable of shortening the time required betweenoptical disk insertion and transition to standby.

DISCLOSURE OF THE PRESENT INVENTION

[0010] An object of the present invention is therefore to provide amethod of reproducing an optical disk that shortens the time betweenoptical disk insertion and implementation of a standby mode enablingreproduction.

[0011] Another object of the present invention is to provide an opticaldisk reproducing apparatus that shortens the time between optical diskinsertion and implementation of a standby mode enabling reproduction.

[0012] These objects of the present invention are achieved by a methodof reproducing an optical disk comprising a step of reading reproducingconditions stored in a nonvolatile memory and a step of deciding whetherthe optical disk can be properly reproduced using the read reproducingconditions.

[0013] In a preferred aspect of the present invention, the methodfurther comprises a step of performing a measurement with respect to theoptical disk when it is discriminated that the optical disk cannot beproperly reproduced using the reproducing conditions and specifying newreproducing conditions based on the result of the measurement.

[0014] In another preferred aspect of the present invention, the methodfurther comprises a step of storing the new reproducing conditions inthe nonvolatile memory.

[0015] In another preferred aspect of the present invention, thereproducing conditions include at least conditions concerning focusingand conditions concerning tracking.

[0016] In another preferred aspect of the present invention, theconditions concerning focusing include at least conditions concerningfocusing offset and the conditions concerning tracking include at leastconditions concerning tracking offset.

[0017] The aforesaid objects of the present invention are also achievedby a method of reproducing an optical disk comprising a first step ofperforming a measurement with respect to the optical disk to bereproduced and specifying reproducing conditions based on the result ofthe measurement and a second step of saving the reproducing conditions.

[0018] In another preferred aspect of the present invention, the methodfurther comprises a third step of reading the saved reproducingconditions in response to the optical disk being ejected and a nextoptical disk being inserted.

[0019] In another preferred aspect of the present invention, the methodfurther comprises a fourth step of deciding whether the next opticaldisk can be properly reproduced using the read reproducing conditionsand a fifth step of implementing a standby mode without executing thefirst step when it is decided that proper reproduction is possible.

[0020] The aforesaid objects of the present invention are also achievedby an optical disk reproducing apparatus capable of reproducing multipletypes of optical disks comprising first means for storing optical diskreproducing conditions, second means for deciding whether an opticaldisk can be properly reproduced using the reproducing conditions storedin the first means, and third means for discriminating the type of theoptical disk when the second means decides that the optical disk cannotbe properly reproduced using the reproducing conditions.

[0021] In a preferred aspect of the present invention, the apparatusfurther comprises fourth means for storing in the first means newreproducing conditions matched to the type discriminated by the thirdmeans.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]FIG. 1 is a diagram schematically showing the essential portion ofan optical disk reproducing apparatus that is a preferred embodiment ofthe present invention.

[0023]FIG. 2 is a flow chart schematically showing a method ofreproducing an optical disk using an optical disk reproducing apparatus,which is a preferred embodiment of the method of the present invention.

[0024]FIG. 3 is a flow chart schematically showing a method ofrecording/reproducing an optical disk using an optical diskrecording/reproducing apparatus, which is another preferred embodimentof the method of the present invention.

[0025]FIG. 4 is a flow chart schematically showing the sequence ofoperations conducted in a conventional optical disk reproducingapparatus between optical disk insertion and implementation of a standbymode.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Preferred embodiments of the present invention will now bedescribed in detail with reference to the accompany drawings.

[0027]FIG. 1 is a diagram schematically showing the essential portion ofan optical disk reproducing apparatus that is a preferred embodiment ofthe present invention.

[0028] As shown in FIG. 1, the optical recording apparatus of thisembodiment is equipped with a spindle motor 2 for rotating an opticaldisk 1, an optical head 3 for projecting a laser beam onto the opticaldisk 1 and receiving light reflected from the optical disk 1, acontroller 4 for controlling the operations of the spindle motor 2 andthe optical head 3, a nonvolatile memory 5 for storing variousparameters, a volatile memory 6 for temporarily storing the parametersand other data, a laser driving circuit 7 for feeding a laser drivingcurrent to the optical head 3 and a lens driving circuit 8 for feeding alens driving current to the optical head 3. Although no limitation isintended, the optical disk reproducing apparatus of this embodiment is aDVD player configured to be capable of reproducing both CDs and DVDs asthe optical disk 1. The CDs that can be reproduced by the optical diskreproducing apparatus of this embodiment include not only the read-onlyCD (CD-ROM) but also the CD-R and CD-RW recorded with reproducible data.Similarly, the DVDs that can be reproduced include not only theread-only DVD (DVD-ROM) but also the DVD-R and DVD-RW recorded withreproducible data. Among these reproducible optical disks 1, the CD-RWand DVD-RW are so-called phase-change disks characterized in having muchlower laser beam reflection coefficients than the read-only CD and thelike.

[0029] The nonvolatile memory 5 must be rewritable and be capable ofretaining data even after power cutoff but is not particularly limitedas to type. There can, for example, be used a semiconductor memory suchas a flash memory, EEPROM or FRAM (ferroelectric memory) or a magneticrecording medium, typically a hard disk, or the like. The volatilememory 6 must be rewritable but is not particularly limited as to type.There can, for example, be used a semiconductor memory such as a DRAM orSRAM. The nonvolatile memory 5 and volatile memory 6 need not becomponents separate of the controller 4 but can instead be incorporatedin the controller 4.

[0030] Further, as shown in FIG. 1, the controller 4 includes a focusingservo circuit 9, a tracking servo circuit 10, a servo error detectioncircuit 11 and a laser control circuit 12. When the focusing servocircuit 9 is activated, the focusing comes into a state of falling onthe recording surface of the rotating optical disk 1, and when thetracking servo circuit 10 is activated, the spot of the laser beam comesinto an automatic tracking state with respect to the eccentric signaltrack of the optical disk 1. The servo error detection circuit 11 is acircuit for detecting whether the signals that the optical head 3 inputsto the focusing servo circuit 9 and the tracking servo circuit 10 arewithin allowable ranges and whether the drive current of the laserdriving current supplied by the laser driving circuit 7 and the drivecurrent of the lens driving current supplied by the lens driving circuit8 exceed prescribed values. The laser control circuit 12 is a circuitfor controlling the drive current of the laser driving current suppliedby the laser driving circuit 7 so that the laser power always remainsconstant even if the temperature environment changes.

[0031] The focusing servo circuit 9 and the tracking servo circuit 10are respectively provided with auto-gain control for automaticallyregulating the focusing gain and auto-gain control for automaticallyregulating tracking gain.

[0032] The focusing servo circuit 9, tracking servo circuit 10, servoerror detection circuit 11 and laser control circuit 12 need not becircuits incorporated in the controller 4 but can instead be componentsseparate of the controller 4. Moreover, they do not have to be physicalcircuits but can instead be accomplished by programs executed in thecontroller 4.

[0033] The method of reproducing an optical disk using the optical diskreproducing apparatus of this embodiment will now be explained.

[0034]FIG. 2 is a flow chart schematically showing a method ofreproducing an optical disk using the optical disk reproducing apparatusof this embodiment.

[0035] As shown in FIG. 2, at the start the optical disk is insertedinto the optical disk reproducing apparatus (step S11), and thecontroller 4 first reads the various parameters stored in thenonvolatile memory 5 (step S12). The various parameters stored in thenonvolatile memory 5 include a parameter P0 for defining laserwavelength, a parameter P1 for defining focusing gain and a parameter P2for defining tracking gain. This will be explained in more detail later.

[0036] After completing readout of the parameters, the controller 4drives the spindle motor 2 to rotate the optical disk 1, uses the laserdriving circuit 7 to drive the optical head 3, and then, based on theparameter P0 (for defining laser wavelength) among the parameters P0-P2read in step S12, projects a laser beam having the selected wavelengthonto the recording surface of the optical disk 1 (step S13). Two laserbeam wavelengths are used in this embodiment, one for CD type opticaldisks (CD-ROM, CD-R and CD-RW) and the other for DVD type optical disks(DVD-ROM, DVD-R, DVD-RW and DVD-RAM). The former wavelength is about 780nm and the latter is about 650 nm. The controller 4 next operates thelens driving circuit 8 to move the optical head 3 to home position (stepS14).

[0037] The controller 4 then conducts a focusing search by which itdecides the focusing position (step S15). In the focusing search, theoptical head 3 is driven perpendicularly with respect to the recordingsurface of the optical disk 1 under the control of the lens drivingcircuit 8, thereby deciding the position of the optical head 3 in thevertical direction.

[0038] The controller 4 next sets the focusing gain based on theparameter P1 (for defining focusing gain) among the parameters P0-P2read in step S12 (step S16). By “focusing gain” is meant theamplification factor of the lens driving circuit 8 for making the laserbeam automatically track the recording surface of the optical disk 1based on a focusing error signal. While other possibilities also exist,in step S16 it is one or the other of a “High” gain and a “Low” gainselected based on the parameter P1. An optical disk 1 that requires thefocusing gain to be set to “High” is one of a type having a lowcoefficient of reflection, namely, a phase-change disk such as a CD-RW,DVD-RW or DVD-RAM. An optical disk 1 that requires the focusing gain tobe set to “Low” is one of a type having a high coefficient ofreflection, namely, a CD-ROM, DVD-ROM or other such read-only diskmanufactured using a stamper having pits formed in advance in accordancewith the data to be recorded, or a CD-R, DVD-R or other recordable diskhaving a dye layer.

[0039] After completing the focusing search (step S15) and the settingof the focusing gain (step S16) in this manner, the controller 4activates the focusing servo circuit 9. That is, it turns the focusingon (step S17). As a result, the focusing comes into a state of fallingon the recording surface of the rotating optical disk 1. When thefocusing servo circuit 9 is activated, the focusing gain isautomatically regulated by the auto-gain control.

[0040] Next, the controller 4 sets the tracking gain based on theparameter P2 (for defining tracking gain) among the parameters P0-P2read in step S12 (step S18). While other possibilities also exist, instep S18 one or the other of a “High” gain and a “Low” gain selectedbased on the parameter P2. An optical disk 1 that requires the trackinggain to be set to “High” is one of a type having a small tracking errorsignal amplitude, namely, a DVD-RW in a push-pull or other such ordinaryoptical detection system. An optical disk 1 that requires the trackinggain to be set to “Low” is one of a type having a large small trackingerror signal amplitude, namely, a CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-R,DVD-RAM.

[0041] After completing setting of the tracking gain (step S18) in thismanner, the controller 4 activates the tracking servo circuit 10. Thatis, it turns the tracking on (step S19). As a result, the spot of thelaser beam comes into an automatic tracking state with respect to theeccentric signal track. When the tracking servo circuit 10 is activated,the tracking gain is automatically regulated by the auto-gain control.

[0042] In the course of the aforesaid different setting operations usingthe parameters P0-P2 read in step S12, the controller 4 keeps the servoerror detection circuit 11 constantly active, and the servo errordetection circuit 11 decides whether some error has been detected andalso decides whether the reading of data from the optical disk 1 can beperformed normally (step S20).

[0043] When it is found that no error has occurred and that data readoutcan be performed normally, the controller 4 decides that appropriatefocusing and appropriate tracking are being performed and conductsinitialization consisting of address detection, reading of filemanagement information and the like (step S21). When this is completed,the standby mode is assumed (step S22). When it is decided in step S20that appropriate focusing and/or appropriate tracking are not beingperformed, the controller 4 carries out the series of step explainedbelow.

[0044] A decision here that appropriate focusing and appropriatetracking are being conducted means that the parameters P0-P2 read fromthe nonvolatile memory 5 match the type of the inserted optical disk 1.For instance, if the parameters stored in the nonvolatile memory 5 wereones for a CD-ROM (or CD-R), it means that the inserted optical disk 1is a CD-ROM (or CD-R). In this case, the controller 4 can read the datastored in the inserted optical disk 1 normally. To the contrary, adecision that appropriate focusing and appropriate tracking are notbeing conducted means that the parameters P0-P2 read from thenonvolatile memory 5 do not match the type of the inserted optical disk1. This happens, for instance, in the case where the parameters storedin the nonvolatile memory 5 are ones for a DVD-R and the insertedoptical disk 1 is a CD-RW. In this case, the controller 4 cannot readthe data stored in the inserted optical disk 1 normally.

[0045] When it is decided in step S20 that appropriate focusing and/orappropriate tracking is not being performed, because the servo errordetection circuit 11 detected some error or because normal reading ofdata cannot be performed, the controller 4 repeats the focusing search(step S23). In this focusing search, the optical head 3 is drivenperpendicularly to the recording surface of the optical disk 1.

[0046] This focusing search is carried out by conducting a focusingsearch using the currently selected laser wavelength, i.e., using thelaser wavelength selected based on the parameter P0, and if a validphotodiode detection signal cannot be obtained from the optical head 3,the focusing search is conducted again at a different laser wavelength.When a valid photodiode detection signal is obtained from the opticalhead 3 in this manner, digital data representing the laser wavelengthused at that time is temporarily stored in the volatile memory 6 as theparameter P0 (step S24).

[0047] During this focusing search, the controller 4 detects thereflection level of the optical disk 1 (step S25) and sets the focusinggain (step S26). As explained earlier, some types of the optical disk 1have a low coefficient of reflection with respect to the laser beam(CD-RW, DVD-RW and DVD-RAM) and other types thereof have a highcoefficient of reflection (CD-ROM, CD-R, DVD-ROM AND DVD-R). In thesetting of the focusing gain (step S26), an appropriate focusing gainselected based on the reflection level detected in step S25 is set.While other possibilities exist, in step S26, “High” focusing gain isselected if the reflection level detected in step S25 does not exceed aprescribed value and “Low” focusing gain is selected if the reflectionlevel detected in step S25 exceeds the prescribed value. The controller4 temporarily stores digital data representing the selected and setfocusing gain in the volatile memory 6 as the parameter P1 (step S27).

[0048] After completing the setting of the focusing gain (step S26) andthe storage of the parameter P1 (step S27) in this manner, thecontroller 4 activates the focusing servo circuit 9. That is, it turnsthe focusing on (step S28). As a result, the focusing comes into a stateof falling on the recording surface of the rotating optical disk 1. Whenthe focusing servo circuit 9 is activated, the focusing gain isautomatically regulated by the auto-gain control.

[0049] The controller 4 then measures the tracking error signalamplitude (step S29) and sets the tracking gain (step S30). As explainedearlier, some types of the optical disk 1 have a small tracking errorsignal amplitude and other types have a large tracking error signalamplitude. In this setting of the tracking gain (step S30) anappropriate tracking gain selected based on the tracking error signalamplitude measured in step S29 is set. While other possibilities exist,in step S30, “High” tracking gain is selected if the tracking errorsignal amplitude detected in step S29 does not exceed a prescribed valueand “Low” tracking gain is selected if the tracking error signalamplitude detected in step S29 exceeds the prescribed value. Thecontroller 4 temporarily stores digital data representing the selectedand set tracking gain in the volatile memory 6 as the parameter P2 (stepS31).

[0050] After completing setting of the tracking gain (step S30) andstorage of the parameter P2 (step S31) in this manner, the controller 4activates the tracking servo circuit 10. That is, it turns the trackingon (step S32). As a result, the spot of the laser beam comes into anautomatic tracking state with respect to the eccentric signal track. Asexplained earlier, when the tracking servo circuit 10 is activated, thetracking gain is automatically regulated by the auto-gain control.

[0051] When activation of the focusing servo circuit 9 and the trackingservo circuit 10 have been completed in the foregoing manner, thecontroller 4 conducts the aforesaid initialization (step S21). When thisis completed, the standby mode is assumed (step S22). As was mentionedabove, standby is a state in which the apparatus waits for aninstruction from the user, and when the user enters an instruction toreproduce the optical disk, reproduction begins.

[0052] When the user enters an instruction to eject the optical disk 1(step S33), the controller 4 reads the parameters P0-P2 stored in thevolatile memory 6 and writes them to the nonvolatile memory 5 (stepS34), whereafter the optical disk 1 is ejected (step S35). However, whenthe parameters P0-P2 are not contained in the volatile memory 6, i.e.,when it was decided in step S20 that appropriate focusing andappropriate tracking were being performed, the writing to thenonvolatile memory 5 (step S34) is skipped.

[0053] As a result of the foregoing, parameters P0-P2 matched to thetype of optical disk 1 most recently reproduced are stored in thenonvolatile memory 5. If the same type of optical disk 1 is nextreproduced, therefore, the parameters P0-P2 stored in the nonvolatilememory 5 can be used (the steps S23 to S32 can be skipped) to rapidlyestablish the standby mode. Of particular note is that in a situationwhere the user mainly uses only a specific type of optical disk 1 andalmost never uses another type of optical disk, the stress experiencedby the user is minimized because the steps S23 to S32 are almost alwaysskipped.

[0054] Thus, owing to the fact that parameters P0-P2 matched to the mostrecently reproduced optical disk 1 are stored in the nonvolatile memory5 in this embodiment, the time between insertion of an optical disk 1and transition to the standby mode enabling reproduction can beshortened.

[0055] Another preferred embodiment of the present invention will now beexplained.

[0056] This embodiment represents an example of applying the presentinvention to an optical disk recording/reproducing apparatus capable notonly of reproducing an optical disk 1 but also of performing datarecording with respect to an optical disk 1. The optical diskrecording/reproducing apparatus of this embodiment is configuredsimilarly to the optical disk reproducing apparatus shown in FIG. 1 butit differs form the optical disk reproducing apparatus of the precedingembodiment in the point that the focusing-related settings andtracking-related settings are conducted more rigorously in order toachieve accurate recording of data on the optical disk 1. Note that inthis embodiment the laser control circuit 12 controls the drive currentof the laser driving current during reproduction so that, as mentionedearlier, the laser power always remains constant even if the temperatureenvironment changes and controls the drive current of the laser drivingcurrent during recording so as to produce laser pulses suitable for thedisk properties.

[0057] The method of optical disk recording/reproducing using an opticaldisk recording/reproducing apparatus of this embodiment will now beexplained.

[0058]FIG. 3 is a flow chart schematically showing the method ofrecording/reproducing an optical disk using an optical diskrecording/reproducing apparatus in accordance with this embodiment Stepsin FIG. 3 that are the same as those shown in FIG. 2 are assigned thesame reference symbols as those in FIG. 2.

[0059] As shown in FIG. 3, at the start the optical disk is insertedinto the optical disk reproducing apparatus (step S11), and thecontroller 4 first reads the various parameters stored in thenonvolatile memory 5 (step S12). In this embodiment, the variousparameters stored in the nonvolatile memory 5 include not only aparameter P0 for defining laser wavelength, a parameter P1 for definingfocusing gain and a parameter P2 for defining tracking gain, but also aparameter P3 for defining amount of tracking offset and a parameter P4for defining amount of focusing offset.

[0060] After completing readout of the parameters, the controller 4drives the spindle motor 2 to rotate the optical disk 1, drives theoptical head 3, and then, based on the parameter P0 (for defining laserwavelength) among the parameters P0-P4 read in step S12, projects alaser beam having the selected wavelength onto the recording surface ofthe optical disk 1 (step S13). The controller 4 next operates the lensdriving circuit 8 to move the optical head 3 to home position (stepS14).

[0061] Next, as in the preceding embodiment, the controller 4 conducts afocusing search (step S15), sets the focusing gain based on theparameter P1 for defining focusing gain (step S16), and activates thefocusing servo circuit 9. That is, it turns the focusing on (step S17).As a result, the focusing comes into a state of falling on the recordingsurface of the rotating optical disk 1 and the focusing gain isautomatically regulated by the auto-gain control.

[0062] Then, as in the preceding embodiment, the controller 4 sets thetracking gain based on the parameter P2 for defining tracking gain (stepS18).

[0063] After completing setting of the tracking gain (step S18) in thismanner, the controller 4 adjusts the tracking offset based on based onthe parameter P3 (for defining amount of tracking offset) among theparameters P0-P4 read in step S12 (step S36).

[0064] Then the controller 4 activates the tracking servo circuit 10.That is, it turns the tracking on (step S19). As a result, the spot ofthe laser beam comes into an automatic tracking state with respect tothe eccentric signal track and the tracking gain is automaticallyregulated by the auto-gain control.

[0065] Further, the controller 4 adjusts the focusing offset based onbased on the parameter P4 (for defining amount of focusing offset) amongthe parameters P0-P4 read in step S12 (step S37).

[0066] In the course of the aforesaid different setting operations usingthe parameters P0-P4 read in step S12, the controller 4 keeps the servoerror detection circuit 11 constantly active as in the precedingembodiment, and the servo error detection circuit 11 decides whethersome error has been detected and also decides whether the reading ofdata from the optical disk 1 can be performed normally (step S20).

[0067] When it is found that no error has occurred and that data readoutcan be performed normally, the controller 4 decides that appropriatefocusing and appropriate tracking are being performed and conductsinitialization consisting of address detection, reading of filemanagement information and the like (step S21). When this is completed,the standby mode is assumed (step S22). When it is decided in step S20that appropriate focusing and/or appropriate tracking are not beingperformed, the controller 4 carries out the series of step explainedbelow.

[0068] When it is decided in step S20 that appropriate focusing and/orappropriate tracking is not being performed, because the servo errordetection circuit 11 detected some error or because normal reading ofdata cannot be performed, the controller 4, as in the precedingembodiment, conducts another focusing search (step S23), stores theparameter P0 (step S24), detects the reflection level (step S25), setsthe focusing gain (step S26), and stores the parameter P1 (step S27),whereafter it activates the focusing servo circuit 9. That is, it turnsthe focusing on (step S28). As a result, the focusing comes into a stateof falling on the recording surface of the rotating optical disk 1.

[0069] As in the preceding embodiment, the controller 4 then measuresthe tracking error signal amplitude (step S29) and sets the trackinggain (step S30). Also as in the preceding embodiment, the controller 4at this point temporarily stores digital data representing the trackinggain selected by tracking gain setting (step S30) in the volatile memory6 as the parameter P2 (step S31).

[0070] After completing setting of the tracking gain (step S30) andstorage of the parameter P2 (step S31) in this manner, the controller 4internally regulates the direct current (DC) component of the trackingerror signal electrically so that the direct current component containedin the tracking error becomes 0 V. That is, it adjusts the trackingoffset (step S38). Moreover, the controller 4 temporarily stores digitaldata representing the amount of offset required for the tracking offsetadjustment in the volatile memory 6 as the parameter P3 (step S39).

[0071] After completing the tracking offset adjustment (step S38) andthe storage of the parameter P3 (step S39), the controller 4 activatesthe tracking servo circuit 10. That is, it turns the tracking on (stepS32). As a result, the spot of the laser beam comes into an automatictracking state with respect to the eccentric signal track. In this case,since the tracking offset was adjusted in step S38, the laser beam spottraces substantially the center of the signal track.

[0072] After completing the tracking-related setting/adjustment in theforegoing manner, the controller 4 internally imparts offset current tothe focusing servo signal so as to optimize jitter and error rate asreproduction quality factors, thereby electrically regulating thefocusing servo signal. That is, it adjusts the focusing offset (stepS40). Moreover, the controller 4 temporarily stores digital datarepresenting the amount of offset required for the focusing offsetadjustment in the volatile memory 6 as the parameter P4 (step S41).

[0073] Next, as in the preceding embodiment, the aforesaidinitialization (step S21) is conducted, whereafter the standby mode isassumed (step S22). As was mentioned above, standby is a state in whichthe apparatus waits for an instruction from the user. When the userenters an instruction to reproduce the optical disk, reproductionbegins, and when the user enters an instruction to record to the opticaldisk 1, recording begins. In recording to the optical disk 1, it isordinarily necessary to set and regulate the focusing and tracking withhigh accuracy. In this embodiment, the focusing and tracking are veryaccurately set and regulated owing to the fact that tracking offset(step S36, step S38) and focusing offset adjustment (step S37, S40) arecarried out.

[0074] When the user enters an instruction to eject the optical disk 1(step S33), the controller 4 reads the parameters P0-P4 stored in thevolatile memory 6 and writes them to the nonvolatile memory 5 (stepS34), whereafter the optical disk 1 is ejected (step S35). However, whenthe parameters P0-P4 are not contained in the volatile memory 6, i.e.,when it was decided in step S20 that appropriate focusing andappropriate tracking were being performed, the writing to thenonvolatile memory 5 (step S34) is skipped.

[0075] As a result of the foregoing, similarly to in the precedingembodiment, parameters P0-P4 matched to the type of optical disk 1 mostrecently reproduced are stored in the nonvolatile memory 5. If the sametype of optical disk 1 is next reproduced, therefore, the parametersP0-P4 stored in the nonvolatile memory 5 can be used (the steps S23 toS32 and steps S38 to S41 can be skipped) to rapidly establish thestandby mode. A particular point worth noting is that, in comparisonwith a read-only apparatus that cannot record, an optical diskrecording/reproducing apparatus requires a larger number ofsetting/regulation steps to be conducted after an optical disk 1 isinserted, so that more time is ordinarily need to reach the standbymode. In the present embodiment, however, the standby mode can berapidly established when again using an optical disk of the same type asthe optical disk 1 most recently used, because parameters P0-P4 requiredfor the settings and regulation are stored in the nonvolatile memory 5.

[0076] The present invention has thus been shown and described withreference to specific embodiments. However, it should be noted that thepresent invention is in no way limited to the details of the describedarrangements but changes and modifications may be made without departingfrom the scope of the appended claims.

[0077] For example, in the above-described embodiments, parameters arewritten to the nonvolatile memory 5 between the time that the userenters an instructions to eject the optical disk 1 (step S33) and thetime that the optical disk 1 is actually ejected (S35). However, thewriting of the parameters to the nonvolatile memory 5 is not limited tothis period and can, for example, be conducted during standby (step S22)or be conducted during reproduction (recording) of the optical disk 1.Moreover, it can be conducted after or during the ejection of theoptical disk 1 (step S35) or be conducted during initialization (stepS21).

[0078] In the foregoing embodiments, the generated parameters are oncestored in the volatile memory 6 and later stored in the nonvolatilememory 5. However, it is instead possible to store each parameter in thenonvolatile memory 5 as it is generated.

[0079] In the foregoing embodiments, the parameters are read from thenonvolatile memory 5 between the time that the optical disk 1 isinserted (step S11) and the time that the optical disk 1 is rotated andthe laser beam is projected thereon (step S13). However, the reading ofthe parameters from the nonvolatile memory 5 is not limited to thisperiod and can be conducted anytime before the focusing gain is decided(step S16). The reading of the parameters can therefore be conductedbefore insertion of the optical disk 1.

[0080] The parameters stored in the nonvolatile memory 5 in theforegoing embodiments are only one example of the parameters to bestored in the present invention and it is possible to store only some ofthem in the nonvolatile memory 5 or to also store other parameters inthe nonvolatile memory 5.

[0081] In step S23 of the foregoing embodiments, a focusing search isconducted using the currently selected laser wavelength, i.e., using thelaser wavelength selected based on the parameter P0. However, in stepS23 it is instead possible to select and conduct the focusing searchusing a specific laser wavelength (such as 780 nm) unrelated to thecurrently selected laser wavelength.

[0082] In step S12 of the foregoing embodiments, parameters stored inthe nonvolatile memory 5 are read. In a case where a next optical disk 1is inserted following the ejection of the preceding optical disk 1without cutting off the power, the readout from memory in step S12 canbe readout from the volatile memory 6.

[0083] Further, in this specification and the appended claims, therespective means need not necessarily be physical means and arrangementswhereby the functions of the respective means are accomplished bysoftware fall within the scope of the present invention. In addition,the function of a single means may be accomplished by two or morephysical means and the functions of two or more means may beaccomplished by a single physical means.

[0084] As explained in the foregoing, the present invention provides amethod of reproducing an optical disk and an optical disk reproducingapparatus that that shorten the time between optical disk insertion andimplementation of a standby mode enabling reproduction.

1. A method of reproducing an optical disk comprising: a step of readingreproducing conditions stored in a nonvolatile memory, and a step ofdeciding whether the optical disk can be properly reproduced using theread reproducing conditions.
 2. A method of reproducing an optical diskas claimed in claim 1, further comprising a step of performing ameasurement with respect to the optical disk when it is discriminatedthat the optical disk cannot be properly reproduced using thereproducing conditions and specifying new reproducing conditions basedon the result of the measurement.
 3. A method of reproducing an opticaldisk as claimed in claim 2, further comprising a step of storing the newreproducing conditions in the nonvolatile memory.
 4. A method ofreproducing an optical disk comprising: a first step of performing ameasurement with respect to an optical disk to be reproduced andspecifying reproducing conditions based on the result of themeasurement, and a second step of saving the reproducing conditions. 5.A method of reproducing an optical disk as claimed in claim 4, furthercomprising a third step of reading the saved reproducing conditions inresponse to the optical disk being ejected and a next optical disk beinginserted.
 6. An optical disk reproducing apparatus capable ofreproducing multiple types of optical disks comprising: first means forstoring optical disk reproducing conditions, second means for decidingwhether an optical disk can be properly reproduced using the reproducingconditions stored in the first means, and third means for discriminatingthe type of the optical disk when the second means decides that theoptical disk cannot be properly reproduced using the reproducingconditions.
 7. An optical disk reproducing apparatus as claimed in claim6, further comprising fourth means for storing in the first means newreproducing conditions matched to the type discriminated by the thirdmeans.